Risk Factors for Gastric Cancer
Gastric cancer risk assessment requires identifying specific high-risk populations and modifiable factors, with chronic Helicobacter pylori infection serving as the primary driver, particularly when combined with demographic, dietary, and socioeconomic risk factors. 1
High-Risk Populations Requiring Screening Consideration (Age ≥45 years)
Geographic and Ethnic Risk Factors
- Early-generation immigrants from moderate-to-high incidence regions (GC incidence ≥10-12 per 100,000):
- Eastern Europe
- Andean Latin America
- East Asia 1
- Non-White racial/ethnic groups with established moderate-to-high GC incidence
- Ethnic enclave effects: Individuals with highest enclave (least acculturation) and lowest socioeconomic status carry highest risk 1
Family History
- First-degree relative with gastric cancer (screening should start 10 years earlier than youngest affected relative) 1, 2
Hereditary Syndromes
- Familial adenomatous polyposis
- Peutz-Jeghers syndrome
- Juvenile polyposis
- MUTYH-associated polyposis
- Lynch syndrome
- Hereditary breast and ovarian cancer syndrome
- Li-Fraumeni syndrome 1
Infectious Risk Factors
Helicobacter pylori Infection
Chronic H. pylori infection is the most significant modifiable risk factor for non-cardia gastric cancer 3, 4. Risk substantially increases when combined with:
Important distinction: H. pylori is primarily associated with non-cardia gastric cancer; evidence for cardia gastric cancer association is conflicting, though some East Asian data suggests possible involvement 3
Other Infectious Agents
- Epstein-Barr virus
- Human cytomegalovirus 5
Dietary Risk Factors
High-Risk Dietary Patterns
Multiple meta-analyses consistently demonstrate:
- High-salt diet (stronger association with non-cardia GC) 1, 3, 6
- Red and processed meats 1, 3, 6
- Bacon consumption (strong evidence) 6
- Low intake of fresh fruits (<100g daily) 2
Protective Dietary Factors (Strong Evidence)
- Dietary total antioxidant capacity
- Vegetable fat
- Cruciferous vegetables and cabbage
- Total vitamin intake, particularly vitamins A and C 6
Lifestyle and Behavioral Risk Factors
Tobacco and Alcohol
- Smoking: Risk factor regardless of anatomical location (cardia vs. non-cardia) 3, 4
- Alcohol consumption: Associated with increased risk across all gastric cancer types 3
Obesity
- Established risk factor for cardia gastric cancer
- Relationship with non-cardia gastric cancer requires further research 3
Anthropometric Measures
- Increased waist circumference (strong evidence) 6
Socioeconomic and Environmental Risk Factors
Persistent Poverty
GC mortality rates are 43% higher in US counties under persistent poverty designation (compared to 17.7% for colorectal cancer and 12.3% for all cancers combined) 1. This reflects:
- Exposure to environmental carcinogens
- Limited access to quality healthcare
- Secondhand smoke exposure
- Poor dietary quality 1
Environmental Exposures
- Air pollution
- Water quality issues
- Soil pollution
- Radiation exposure
- Altitude and climate factors 5
Endoscopic and Histologic Risk Factors
Premalignant Gastric Conditions
In patients >10 years post-H. pylori eradication:
- Open-type atrophy (OR 10.40; strongest independent risk factor) 7
- Severe intestinal metaplasia (OR 5.15) 7
- Gastric xanthoma (more prevalent in precancerous lesions and GC) 2
- Map-like redness 7
Other Gastric Conditions
Age and Sex
- Age ≥50 years: Independent risk factor 2
- Male sex: Consistently higher risk 2, 4
- Rural residence: Associated with increased risk 2
Medical History
- Hypertension: Independent risk factor for both precancerous lesions and GC 2
Clinical Pitfalls and Caveats
Critical consideration: Risk assessment cannot rely on single factors. A personalized approach combining multiple risk factors is essential, particularly for individuals ≥45 years with chronic or former H. pylori infection plus additional behavioral determinants 1.
Important note: Insufficient data exists to recommend screening based solely on high-risk behaviors (smoking, diet) or poverty status without other risk factors 1.
Protective factors paradox: History of gastric or duodenal ulcer and presence of fundic gland polyps were associated with lower long-term GC risk post-eradication 7, though the mechanism remains unclear.